There would need to be an entire reinterpretation of the Constitution, likely beginning with the Tenth Amendment which said that the Constitution, as written, gave only those specific powers expressly written into the document to the federal government and that every other action, such as the implied commerce course, is illegal under the Tenth Amendment. This will serve to give the states the majority power over anything that the Constitution did not expressly say the federal government could do. So, any laws that hinge on the commerce clause for thier support, such as discrimination in hotels due to commerce clause, would be illegal.